This publication was created in conjunction with the Family Village Project. The Family Village Project is sponsored by the Joseph P. Kennedy Jr. Foundation, the Mitsubishi Electric America Foundation, and the Waisman Center at the University of Wisconsin-Madison.
Originally, the Internet was intended to facilitate communication and the sharing of computer resources among far-flung scientific researchers. (Yes, the Internet really was used by honest-to-goodness rocket scientists.) It worked so well that it soon advanced far beyond its original mission. Today, the Internet is used by millions of people from all walks of life (that is, non-rocket scientists) for communicating, presenting, and gathering information, and just plain having fun. Thousands of organizations and companies use the Internet to advertise, inform, distribute software, gather feedback, and process customer orders.
You should care about the Internet because it can provide, inexpensively and 24-hours-a-day, services that you can get no where else. What services? They include the ability to
Here are some minimal setups needed to access the most useful Internet resources:
Software
Also, you must have a dial-up account from an Internet access provider (e.g. a university, on-line information service such as Prodigy or the Microsoft Network, or a local Internet access company.)
The minimum cost ranges from around $10 to $30 per month to be connected via an on-line service or Internet access company.
To send an email message, all you need is to be connected to the Internet, have an email program on your computer, and know the email address of the person with whom you want to communicate. For example, one popular email program for both IBM-compatible computers and Macintoshes is called Eudora. It looks like this:
In this case, the email address of the recipient is
rowley@waisman.wisc.edu
The part before the @ symbol identifies the person and is often a portion of their name. The part after the @ symbol identifies the host, or computer that maintains their email account. Just like a regular address tells the Postal Service where a letter should be sent, an email address tells the Internet where an email message should be sent. The sender’s address is sent along with the message so that the recipient knows who sent it and can reply. Also, if for some reason the message cannot be delivered, the sender will be automatically notified by email.
To send this message, all colantonio has to do is click the Send button. In a manner of seconds or minutes, the recipient rowley will be notified that new mail has arrived and she can read it immediately or wait until later. Even if the recipient is not using her computer, any email message that arrives will be stored in her personal "mailbox" and kept there until she chooses to read it. Messages can be stored, deleted, forwarded to others, or immediately answered after they are read.
Although most email messages are sent to just one other person, it’s just as easy to send the same message to a few or even many other recipients. The Cc feature, which stands for Carbon Copy, lets you send the same message to one or more other people. Alternately, many email programs let you send the same message to several people by listing their email addresses in the To section of the screen. You can even set up mailing lists consisting of groups of email addresses.
One of the reasons the Internet was established was to facilitate the transfer of files between computers. So, a set of rules, known as a protocol, was agreed upon to make sure that all computers connected to the Internet could send and receive any kind of file. This set of rules is called the File Transfer Protocol, or FTP for short. It works the same whether the computers are in the same building or on different continents. On many systems, the actual program you use to transfer files using this protocol is also named FTP.
An organization that wants to share files sets up an FTP site. It may allow anyone access to this site or restrict access to certain people. Many sites let anyone who uses the name anonymous to enter the system and copy certain files. For example, the Waisman Center has just such a site. Here is a sample session of a program called WS_FTP (an FTP program that runs under Microsoft Windows) that is connected to the Waisman Center’s FTP site:
The box on the right lists files on the Waisman Center computer. The box on the left represents your computer. To transfer a file from the Waisman Center to your computer, you simply highlight the file on the right side and click the button with the arrow pointing to the left.
Of course, you need to know the location and name of a file before you can actually transfer it. Most sites contain one or more files that you can transfer first to tell you the locations and names of the files you seek.
You may also use FTP to send files to certain sites, but this is less common that obtaining files from remote sites.
Scientific researchers often have accounts on several, or even many, different computer systems. For example, an atmospheric scientist may obtain an account on a supercomputer (a really fast and big computer) at a distant university so that she may use its superior mathematical speed to work on weather-prediction problems. Remember that the Internet was originally designed to help researchers collaborate. So, one of the major features of the Internet is that it allows remote access to computers.
This feature, however, is also used by ordinary folk to work on different computers. For example, many people have an account on a computer where they work or go to school. They may also have their own personal desktop or laptop computer at home. By using the remote login capability of the Internet, they can access their computer account at work or school from home, or indeed from any other computer connected to the Internet. And what can they do? Well, they can read their email or send new email messages or look at their own files. In some cases, a person can actually do anything via a remote access that they can do in person.
In addition, some organizations and companies give people temporary or limited access to their computers for special purposes. For example, many academic libraries have their catalogs on-line and accessible to anyone connected to the Internet. At least 500 such catalogs from all over the world are on the Internet and they let anyone peruse bibliographic information about their holdings.
Accessing remote computers over the Internet is possible thanks to a protocol (remember, a protocol is a set of rules) called Telnet. Like FTP, the program that uses the protocol is also called telnet on many computers. The following screen, for example shows the use of a telnet program to access a computer system at the Waisman Center:
Using telnet is easy on most computers. You simply type telnet followed by the name of the computer host you want to access. For example, in the above screen the host name is vranix.waisman.wisc.edu. Once the connection is made, the session proceeds just as if your computer were connected directly to the remote computer.
Each mailing list has its own distribution address, which looks just like a regular email address. All you have to do to get on a mailing list is to "subscribe" by sending email to the list administrator. This administrator may be a real person or an automated list maintenance program. One such program is called LISTSERV (short for List Server). Once you subscribe, your email address will be added to the mailing list, and you’ll start receiving messages from other list members. You may reply to these messages or start new discussions. Any message you send to the email list address will be automatically distributed to every member of that list. Alternatively, you may choose not to participate actively by sending messages at all; you can just "listen" to the discussions (sometimes called lurking).
So, to subscribe to a mailing list on the Internet, you usually send a subscription request to the list’s administrative address, which is distinct from the list’s distribution address. For example, one Internet mailing list on Down Syndrome is named DOWN-SYN. The administrative address for this mailing list is listserv@listserv.nodak.edu. The following screen shows the email message user colantonio would send to subscribe to the DOWN-SYN mailing list:
After subscribing, you will receive a standard letter of welcome (via email) telling you about the list. From that time on, you will receive all mail (postings) sent to the list by its members. You may just follow the discussions (lurk) or join in on them. If you respond, you can send your response to the whole list (in which case, all members of the list will receive it), or to just an individual on the list. For example, to post a message to the entire membership of the Down Syndrome mailing list, you would send an email message to down-syn@listserv.nodak.edu. You can get off the mailing list (unsubscribe) at any time by simply sending an email message to the list administrator (listserv@listserv.nodak.edu) with the command SIGNOFF DOWN-SYN. You can also get a listing of all the members of a list and their email addresses.
A Usenet discussion group is called a newsgroup, and there are thousands of them. (Estimates range from 5,000 to 10,000.) In this context, "news" has no particular relation to current events; Usenet newsgroups cover many diverse topics, some serious and others frivolous. Science, politics, music, philosophy, sex, cooking, skydiving, alien visitors, back rubs, coffee, and limericks, all have one or more Usenet newsgroups devoted to them. Some even cover current events. Every day, hundreds of thousands of people read some Usenet newsgroup.
The main difference between mailing lists and newsgroups is that discussions come directly to all members via email with mailing lists, but with newsgroups you must execute a newsreader program to follow discussions. So, a newsgroup is sort of like a centralized bulletin board where you go to look at messages people post. If you have a newsreader program and access to Usenet, you may read any message posted on any newsgroup. In this sense, newsgroups are more open than mailing lists because you do not need to send an email message to an administrator to be able to follow the discussions.
The following message, for example, was posted on the Usenet newsgroup alt.support.spina-bifida:
Discussion groups on IRC are called channels and they exist only as long as people are participating in them. Anyone can create a new channel and thus become the operator of that channel. Operators have special privileges, such as being able to deny access to certain people and moderate all communication. Some channels are private, while others are public and open to anyone; the operator decides. IRC channels have names that begin with a #. For example, here are a few IRC channels: #atlanta, #comics, #disney, #guitar, #India, #nicecafe, and #xf (for The X-Files TV show fans). To use IRC, you need an IRC program (called a client) on your computer and (of course) a connection to the Internet. You also need to know which IRC network you want to use (there are several, with EFnet and Undernet being the most popular) and which channel you want to use. When you join a channel, you choose a nickname for yourself. Then, everything you type, prefaced with your nickname, will be seen by everyone on the channel. And you will get to see everything typed by everyone else on the channel. It all happens in real-time, with participants identified only by nickname, who may be anywhere in the world.
If you are interested in trying IRC, you can obtain information and free software that runs under Microsoft Windows at this WWW site: http://mirc.stealth.net/
Gopher is an excellent tool for browsing through information. Unlike FTP, Gopher handles all the details of where files are located or how to t ransfer them to your computer. All you do is pick items from menus. Most menus lead to other menus, and so Gopher lets you "burrow" through vast quantities of structured information.
A major advantage of Gopher is that it works on most computers connected to the Internet. In other words, it doesn’t require a sophisticated computer or high-speed network connection to work reasonably well. For example, you can use Gopher on a computer terminal that cannot display graphics. Gopher is, however, still quite easy to use, thanks to its hierarchical menus.
To use Gopher, you need a connection to the Internet and a Gopher program (also called a Gopher client). The best arrangement is to have a Gopher program on your own computer, but it is possible to use Telenet to connect to some other computer and run a Gopher client from there. Either way, to use Gopher you run the client and "point" it at some initial Gopher address. For example, the Trace Research and Development Center at the University of Wisconsin-Madison, affiliated with both the Waisman Center and the Department of Industrial Engineering, has set up a Gopher system to present information about their activities and products. Their Gopher address is:
gopher.trace.wisc.edu
The following screen shows a Gopher client called WSGopher, which runs under Microsoft Windows, accessing the Trace Center’s Gopher system; you can see how a hierarchy of menus was traversed to ultimately retrieve a text document of information about the Trace Center.
Central to the World-Wide Web is the concept of hypertext, or more generally, hypermedia. Hypertext is text that contains words or phrases (called links) that can be chosen by the reader to immediately retrieve and view other text. So, if you were viewing a hypertext document, you could select a highlighted term, and immediately jump to a different document related to that term. Hypermedia extends the scope of hypertext to include pictures, sounds, and even video clips.
The innovation introduced by the World-Wide Web is that hypertext documents may be located anywhere on the Internet. For example, you can be reading a document, select a highlighted term, and immediately jump to another document stored in a computer on the other side of the world.
The popularity of the World-Wide Web really skyrocketed with the introduction in 1993 of a program called Mosaic. This software was developed at the National Center for Supercomputing Applications (NCSA) at the University of Illinois, Urbana-Champaign. Mosaic, unlike the earlier text-only programs, allowed the integration of graphics and let users see different documents by simply pointing and clicking with a mouse. This program was the first of many so-called Web browsers that allow users to access information of all kinds on the World-Wide Web. Today, the most popular Web browser is Netscape Navigator, created by the original developers of Mosaic, after they left the University of Illinois and started their own company.
In simplified terms, here’s how the World-Wide Web works. A company or organization that wants to present information on the World-Wide Web must have a fairly fast, powerful computer connected to the Internet. This computer must be equipped with software called a Web server. The documents to be presented must contain instructions in HyperText Markup Language (HTML), that specify the document’s appearance and identify links to other documents. Users who want to access the World-Wide Web must of course be connected to the Internet and have a Web browser on their computer. A Web browser is a program that lets the user view World-Wide Web documents; it is another example of client software, a program that calls upon the services of server software, usually running on a computer somewhere else on a network. As mentioned earlier, Netscape Navigator is the most popular Web browser today, but several others are also available, including Mosaic from NCSA and Internet Explorer for Windows 95 from Microsoft.
Web servers and Web browsers know how to communicate because they all conform to the HyperText Transfer Protocol (HTTP), a set of rules for moving hypertext (really, hypermedia) documents over the Internet. (Web servers are sometimes called HTTP servers.) Hypermedia documents on the World-Wide Web can be found no matter where they are in the world on the Internet because their location is specified by a Uniform Resource Locator (URL). A URL is like the address of a document on the World-Wide Web. For example, the Family Village has a document on the World-Wide Web with this URL:
http://www.familyvillage.wisc.edu/
The document at this location is the Family Village home page. Documents on the Web are often called pages; the first page you see when you go to a particular place on the Web (or Web site) is often called the home page. Today, hundreds of thousands of organizations, companies, and individuals have World-Wide Web home pages on the Internet. For example, here is the Family Village home page, as viewed with the Netscape Navigator Web browser:
Underlined items are links to other documents (they also appear in a different color on the screen). To go to another document, you simply move the mouse pointer on top of the highlighted item and click the mouse button. The buttons at the top of the screen also make it easy to jump from document to document. You can go back to the previous document or go directly to your home page. You can type a different URL directly into the box entitled Location at the top of the screen. Like most Web browsers, Netscape Navigator lets you save the locations of interesting Web sites as bookmarks to which you can easily return in future sessions.
Last updated 27-July-1997 by Ernie Colantonio.
Document source: http://www.waisman.wisc.edu/~colantonio/internet.html